docker/release.sh: explicitly build amd64 images
docker/release.sh: explicitly build amd64 images

Signed-off-by: Derek Perkins <e1c79a582b6629e6b39e9679f4bb964d25db4aa8@derekperkins.com>

vitessio/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,mahak/vitess